I have a 600 hp Electric Pump on a Vfd at a potable water pumping station. Our power utility has recently swapped power over to a different substation to work on the one that was feeding us previously. When they made this swap our VFD was tripping out on “Fault Supply Phase”. After checking amperage & reviewing Trending from our Power Monitors we found out that the Amperage coming from this other substation was way off balance when we would run our VFDs. The Voltages were, and remain while running within the 3% threshold provided by our Utility but the Amperages between Phases would go off over 40% between 2 legs.
we found this to be happening with smaller, newer VFDs feeding 50hp pumps in the same facility but luckily they were not tripping out from it. When the Utility came out they measured the amperage before and after our transformer on our property and told us that the amperage was low on the 1 leg from both the primary side and the secondary side of our transformer. We have a 480v 1600 amp service at this location.
Here is my question:
Is the Power Utilities required to provide power for our Pump stations to run correctly ? When we have spoke with them they have claimed that they are within ANSI requirements :
Per ANSI Standard C84.1-1995, “Electric supply systems should be designed and operated to limit the maximum voltage unbalance to 3% when measured at the electric utility revenue meter under no-load conditions”. The supply voltage at the meter revenue point are well within the requirements even under full load conditions.
Is there not a requirement for them to give us a balanced Current to operate our equipment ? We have been running our Diesel Pump for 3 weeks & now it needs service so we are hooked to a rental 500 Kw generator in order to run our VFD/600hp Electric Pump sucking 600 gallons a day of Diesel Fuel.
Thank you
JDrais
we found this to be happening with smaller, newer VFDs feeding 50hp pumps in the same facility but luckily they were not tripping out from it. When the Utility came out they measured the amperage before and after our transformer on our property and told us that the amperage was low on the 1 leg from both the primary side and the secondary side of our transformer. We have a 480v 1600 amp service at this location.
Here is my question:
Is the Power Utilities required to provide power for our Pump stations to run correctly ? When we have spoke with them they have claimed that they are within ANSI requirements :
Per ANSI Standard C84.1-1995, “Electric supply systems should be designed and operated to limit the maximum voltage unbalance to 3% when measured at the electric utility revenue meter under no-load conditions”. The supply voltage at the meter revenue point are well within the requirements even under full load conditions.
Is there not a requirement for them to give us a balanced Current to operate our equipment ? We have been running our Diesel Pump for 3 weeks & now it needs service so we are hooked to a rental 500 Kw generator in order to run our VFD/600hp Electric Pump sucking 600 gallons a day of Diesel Fuel.
Thank you
JDrais
